Filter Feature has Text Filters, but I want number filter

Hey all,

I am trying to design a database spreadsheet for work, I am a real estate appraiser and we are constantly juggling tons of sales comp data. So, I've put together a spreadsheet that I thought I had completely ironed out, and professional looking. But when I went to filter the sales, certain columns are not displaying number filters, but text filters instead. I've attached the spreadsheet for reference.

After some searching with some people with similar problems, it appears that the =IF function is causing the problem, and that I have inadvertently told Excel to spit out text displayed as numbers, when it should just be numbers.

The reason for using the =IF Function was so that the spreadsheet wouldn't spit out "#DIV/0!", or "#VALUE!" and look professional.

Take column K for example ($/Unit) - right now I have the formula entered "=IF(E3=" "," ",J3/E3)"

With this entered, the number filter works, and I can search apartment comps by sale price per unit. But, then I have the annoying "#VALUE!" displayed in all columns underneath where future comps will be entered.

If I change the formula to read "=IF(E3=0," ",J3/E3)", the "#VALUE!" disappears, but then the number filter doesn't work, and excel forces Text Filtering.

The number filter is the important part, as this database grows, there will literally be hundreds of apartments to filter through. I need to be able to see results specified within a unit price range.

The tough part is that several other pieces of data that affect the $/unit are subject to similar =IF formulas, so untying the knot to get it to work may be challenging.

Any thoughts? Thanks in advance.